KR890004056B1 - Mode conversion method and circuits for hangeul character display - Google Patents

Abstract

The circuit for displaying character of 80 or 40 character mode selectively using only character generator includes a buffer unit (20) for buffering output signal of a video RAM (10) and transmitting most important beat of flock signal for setting 80 or 40 character mode, a selecting unit (30) for transmitting signal for selecting phonemes and Hangul or English mode enable signal designated by output signal of buffer, and a line buffer unit (60) for driving line and transmitting data from Hangul generator (50) to a shift registor (8) for displaying the character on the CRT.

Description

Mode Conversion Method and Circuit for Hangul Character Display

1 is a block diagram according to the present invention.

2 is an example of 80 or 40 characters Hangul characters.

3 is a detailed circuit diagram of FIG. 1 in accordance with the present invention.

4 is a flow chart according to the present invention.

5 is a block diagram of a conventional CRTC.

6 is a pinout diagram of the motor roller 6845.

* Explanation of symbols for the main parts of the drawings

10: video RAM unit 20: buffer unit

30: selection unit 40: English character generator

50: Hangul character generator 50: line buffer

70: CTR controller

The present invention relates to a circuit capable of generating Hangul characters in a computer system, and in particular, Hangul which can selectively display Hangul characters on a screen by 80 or 40 character mode without changing the existing hardware. A mode conversion method and circuit for character display.

Generally, there are various ways to generate Hangul characters on the display, but the characters have been displayed mainly using CRTC (Cathode Ray Tube Controller).

Looking specifically at the function of the general CRTC, the CRT controller generates four basic signals.

1. Refresh Address: Address of the character needed to refresh the screen.

2. Low select: 7 or 9 behavior values of the dots displayed in order.

3. Video monitor timing: Horizontal and vertical sync signal.

4. Display Enable.

In addition, there are two convenient functions of CRTC city.

1. Catool output: Catoall is a function for indicating specific characters such as underline, frame, arrow, and opposite color. This position can be controlled by special keys or commands.

2. Light pen input: The light pen is a convenient device. It detects when the spot passes through the position where the light pen is placed on the screen, and the approximate position on the screen is calculated from the frame scanning timing.

As shown in Fig. 5, the CRTC is equipped with cathode control, synchronous pulse generation, row selection logic of the external collector gene generator 7, and the like. In addition to the interface, a data processing circuit including an external refresh memory 4, a collector generator 7, a shift register 8, and a video output unit 9 is required.

The CRTC chip is manufactured and provided by various semiconductor companies. The pin arrangement of the motor roller # 6845, which is manufactured by a US semiconductor company, is as shown in FIG. 6 and the function thereof is as follows.

It outputs a row count for the collector generator, a horizontal / vertical sync signal (HS / VS), a blanking signal (BLANK), and a 14-bit refresh address for the RAM buffer. It also has functions of scrolling and paging.

When the screen is full of text and image display, the scrolling function removes the display of the top row to display the next row, shifting the entire row up once and leaving the bottom row. Paging is a function likewise, when the display is full and there is no display input, the whole screen is deleted and the new top row is displayed. It also has a cathode register, a direct pen register, and does not require a line buffer externally.

Programmable features include:

ㅇ Number of horizontal and vertical dots per character

ㅇ Number of horizontal and vertical characters per screen

ㅇ Horizontal, vertical sync position

ㅇ Marking of cathool

The above contents are described on pages 136-137 of "Microcomputer Computer Interface Technology" published by the Korean Mechanics Research Institute. Character data processed by the central processing unit (hereinafter referred to as "CPU") 1 is stored in the CPU 1; When stored in the refresh memory 4 under control, the CRTC 2 reads the contents of the stored refresh memory 4 through the multiplexer (MUX) 3 under the control of the CPU 1 and latches 6. It is input to the character generator 7 through.

The character generator 7 receives a row address signal generated by the CRTC 2 to generate characters that are already formed in a pattern in the character generator 7. Characters generated in the character generator 7 are shifted in the shift register 8 according to the shift clock generated in the CRTC 2 and input to the CRT (not shown) through the video output unit 9. The CRT has displayed characters on the CRT in synchronization with the vertical and horizontal synchronization signals (HS / VS) generated by the CRTC 12. On the other hand, each bit of the refresh memory 4 corresponds to a dot of the CRT in a 1: 1 manner, and the CRT writes 80 characters on one line to display 24 lines and 40 on one line. There is a mode for displaying 24 lines by inserting a ruler. In the conventional CRT apparatus, both modes cannot be used together, and only one mode can be used according to the specifications of the provided CRT. In particular, when displaying Korean characters with CRT, a character generator is provided which can generate Korean characters. In the Korean mode, the hardware configuration itself is used when using the desired mode because 80 and 40 character modes cannot be converted. There was a hassle to convert.

Accordingly, an object of the present invention is to provide a method for displaying Korean characters by freely selecting a desired mode by designating the most significant bit of each data as a logic for selecting the mode in selecting a 80-character and 40-character mode. have.

Another object of the present invention is to provide a circuit capable of performing a high-performance Hangul display in a desired mode at a low cost since the conventionally used without changing the hardware.

Therefore, the present invention for performing the above object is a central processing unit for controlling a text display, a video RAM unit having a random image data processed by the central processing unit (RAM) and the output of the video RAM unit A buffer unit for buffering data and outputting flag information for mode designation of the most significant bit according to the 80-character or 40-character mode stored in the video RAM unit, and decoding the output signal of the buffer unit for selection. A selection unit for outputting Korean and English mode enable signals and selection data for generating Korean initial and final phonemes; an English character generator for generating an English character pattern according to the output of the buffer unit and the selection unit; According to the output of the selection unit, the Hangul consonant / vowel character pattern is generated, and the data output from the Hangul character generator A line buffer unit for driving a line sufficiently to be displayed on a CRT, a shift register for shifting the output of the line buffer unit and the output of the English character generator and outputting the video output unit to the video output unit, and the address of the English and Korean character generators A circuit comprising a CRT controller for supplying a signal and a vertical / horizontal synchronization signal to the CRT, and selection information of Korean and English modes and 40 and 80 character modes designated by the central processing unit. A first step of checking, a second step of calculating the most significant bit value of the buffer unit in accordance with the 40-character and 80-character mode of Hangul in the first step, and the logic of the most significant bit in the 40-character mode in the second step. According to the third step of forming a Hangul character by dividing the left and the right, and the second bit when the most significant bit is high in the 80-character mode in the second step And a fourth step of displaying complete Hangul in the position of Cursor.

Hereinafter, with reference to the drawings of the present invention will be described in detail.

1 is a block diagram according to the present invention, which checks the Hangul and English modes, and processes the input data according to the check mode according to the program and controls each unit to be output to the CRT apparatus, and the central The video RAM unit 10 having randomly processed image data processed by the processing unit (CPU) and the output data of the video RAM unit 10 are buffered, and the true flag signal of the most significant bit is buffered according to the 80 character or 40 character mode. And a buffer unit 20 for decoding the signal output from the buffer unit 20, a selector 30 for outputting a Hangul and English mode enable signal and a Hangul initial and final phoneme selection signal, and the buffer. English character generator 40 for generating English characters by the English character code generated by the unit 20 and the selection control signal output from the selection unit 30, and the data and lines output through the buffer unit 20 The Korean character generator 50 which receives the data output through the unit 30 and generates a consonant and vowel character pattern of Korean characters, and a line to sufficiently display the data output from the Korean character generator 50 on the CRT. The line buffer unit 60 for driving (Line Driving), and the line buffer unit 60 to the shift clock generated by the CRT controller 70 to describe the Hangul character data and the English character data of the English character generator 40 will be described later. A shift register 8 for shifting and outputting the shift register, a video output unit 9 for buffering the output of the shift register 8 to the CRT, a data output of the central processing unit (CPU), and a CRT controller (70). A multiplexer (3) for selectively outputting the refresh address signal generated by the < RTI ID = 0.0 >), < / RTI > ) Constructs.

In FIG. 1, the configuration of the CPU, the multiplexer 3, the video output unit 9, and the CRT block are the same as those of FIG. 5 shown in the related art, and the video RAM unit 10 is also illustrated in FIG. It has the same function as the refresh memory 4 in the figure. Therefore, the line 701 of the CPU is connected so that the address and data are supplied from the CPU to the CRTC 70, and the line 705 of the CRTC 70 is a vertical / synchronous signal to the CRT. (Vsync / Hsync) is connected to supply, the line 702 of the CRTC 70 is connected to supply the refresh address signal to the multiplexer (3), the line 301 of the central processing unit (CPU) is connected to the multiplexer ( 3) Through the video RAM 10, the Korean / English character generation is connected such that code data, English / Korean mode selection flex data, and a control signal for processing the data are output, and the line 703 of the CRTC 70 is output. The Korean / English character generators 50 and 60 are a row address signal supply terminal.

FIG. 2 is an example of displaying the Korean 80-character mode and the 40-character mode for "Han".

Therefore, if one embodiment of the present invention is briefly described on the basis of the above-described configuration, according to the user's selection, Korean or English is selected by the central processing unit (CPU), and 80 and 40 character modes are selected by the Korean. The selected flag information is transmitted to the video RAM unit 10 as a character code to be displayed. The video RAM unit 10 inputs the Korean or English data and the mode flag data into the buffer unit 20 to buffer the data. The enable signal is generated so that the output data of the English buffer portion 20 generates the English characters in the selection portion 30.

Alternatively, the central processing unit (CPU) inputs a control signal according to the English processing to the CRTC 70, the CRTC 70 generates a row address and inputs it to the English character generator (40). At this time, the English character generator 40 generates the English character data and inputs the shift register 70 to lift the video output unit 9 according to the shift register 8 according to the shift generated by the CRTC 70. If you input through CRT, English characters are displayed on CRT.

On the other hand, when processing Hangul characters, the CPU recognizes the Hangul mode and checks whether it is in 80 or 40 character mode. The control signal is applied to the CRTC 70 according to the 80-character mode and the 40-character mode to convert the frequency of the vertical / horizontal synchronization signal supplied to the CRT to synchronize with the display of the Hangul characters. The CPU is stored in the video RAM unit 10 through the multiplexer 3 together with data codes for displaying Korean characters and flag information for mode setting.

For example, in the 40-character Korean mode, the data stored in the video RAM unit 10 and the flag data for mode setting are buffered in the buffer unit 20. When the most significant bit of the data output from the buffer 20 is "low", it constitutes a font of a character corresponding to the left half of the second (b) diagram, and the other half when the most significant bit is "high". The Hangul is displayed by configuring the font of the letter corresponding to the letter. To this end, the selector 30 first outputs the Hangul enable signal, selects the consonant phoneme for the Hangul consonant and the final character, and selects the CPU. The CRTC 70 controls the vertical / horizontal synchronization signal supplied to the CRT by the control signal supplied from the CRT to adjust synchronization according to the 40 character mode, and applies a low address signal to the Hangul character generator 50 to provide a buffer unit ( According to the Hangul code data output from 20), the Hangul character generator 50 generates the corresponding Hangul character data.

At this time, when the data is combined into the desired Hangul through the line buffer unit 60 and input to the shift register 8, the data is shifted by the shift clock generated by the CRTC 70 and input to the CRT through the video output unit 9. It is then displayed on the CRT in synchronization with the 40 character mode.

FIG. 3 is a detailed circuit diagram of FIG. 1 according to the present invention, in which VRAM1-VRAM2 is a video RAM, BUF1-BUF2 is a buffer, NA1-NA3 is a NAND gate, AN1 is an AND gate, and MUX1-. MUX2 is multiplexer, OR-ORl7 is OR gate, CG1, CG3 is Hangul consonant character generator, CG2, CG4 is Hangul vowel character generator, CG5-CG6 is Alpha Bell character generator, CRTC is CRT controller CRT Controller) " BL1-BL2 is a buffer line driver. The video RAM VRAMI-VRAM2 is a DRAM that is generally provided and sufficient, and the buffers BUF1-BUF2 can be a general line buffer.

The multiplexer MUX1 is 74LS139, CG2, CG4, CG5-CG6 # 2764, and CG1, CG3 # 27128. 74LS244 is sufficient for the buffer line drivers BL1-BL2. The portion composed of the video RAMs VRAM1 and VRAM2 corresponds to the video RAM portion 10 of FIG. 1, the portion composed of the buffers BUF1 and BUF2 corresponds to the buffer portion 20, the NAND gates NA1-NA3, The portion composed of the ORA gate, the AND gate AN1, and the multiplexer MUX1-MUX2 corresponds to the selection unit 30, and the portion composed of the alphabet character generators CG5 and CG6 is shown in FIG. Corresponding to the character generator 40, Hangul consonant character generator (CG1, CG3). The part composed of the Hangul mode character generators CG2 and CG4 corresponds to the Hangul character generator 50, and the part composed of the ORA gate OR2-ORl7 and the buffer line BL1-BL2 corresponds to the line buffer part 60. , CRTC is the same as FIG.

Therefore, the low address line RA0-RA3 of the CRTC 70 is connected to the address line of the Korean / English character generator CG1-CG6, and the low address line RA3 of the CRTC 70 is the selector 30. Is connected to the input terminal of the AND gate (AN1). The output terminal Q1 of the multiplexer MUX1 of the selector 30 is connected to the output enable terminal OE of the English character generators CG5 and CG6, and the buffer BUF1 is the most significant bit output terminal Dl5 in Korean. It is connected to the uppermost address lines A11 and Al3 of the character / vowel character generators CG1-CG4, respectively. An output terminal of the buffers BUF1-8UF2 is connected to an input terminal of the multiplexer MUX2, and an output terminal of the buffer BUF2 is connected to an address terminal of the English character generator CG5-CG6.

)이 "로우"일때 인에이블단(

)이 "로우"가 되어 인에이블되면 상기 멀티플렉서(MUX1)의 출력단(Q1)이 "로우'가 되어 영문 캐릭터 제네레이터(CG5,CG6)의 출력 인에이블단(

)을 인에이블 한다. 이때 영문문자가 발생하도록 선택한다. 상기 버퍼(BUF1)의 출력단(Dl4,Dl3)이 모두 "로우"일때 낸드게이트(NA1)의 출력은 "하이"이므로 저항(Rl)을 통한 낸드게이트 (NA3)의 타입력단이 "하이"이므로 저항(Rl)을 통한 낸드게이트(NA3)의 타입력단이 "하이"이므로 낸드게이트(NA3)의 출력은 "로우"가 되어 버퍼라인 드라이버(BL1-BL2)의 출력 인에이블단(

)을 인에이블하므로 한글 자/모음 캐릭터 제네레이터(CG1-CG4)에서 발생된 한글이 오아게이트(OR2-OR17)을 통해 원하는 한글형태로 조합되어 버퍼 라인드라이버(BL1-BL2)을 통해 버퍼링 된 후 제1도의 쉬프트레지스터(8)로 출력 되도록 구성되어 있다.An output terminal of the OR gate OR1 receiving the output of the buffer BUF2 is connected to an input terminal of the AND gate AN1, and the AND gate AN1 is connected to the output of the OR gate OR1 and the CRTC 7D. The output of the low address line RA3 is controlled to control the selection stage 5 of the multiplexer MUX2 to selectively output both inputs. Then, the mode according to Korean and English is determined according to the data output through the buffer BUF1. First, as shown in FIG. 1, the mode setting flag data is transferred from the CPU to the video RAM unit 10. As shown in FIG. When inputted through the buffer BUF1, mode selection data is generated in the buffer BUF1. At this time, it is determined according to the output signal output from all gates (NAI, NA2) connected to the output terminal of the buffer BUF1. The output terminals of the NAND gates NA1 and NA2 are connected to the input terminals A0 and A1 of the multiplexer MUX1 and the output terminals of the multiplexer MUX1

) Is set to "low"

) Becomes " low " and the output terminal Q1 of the multiplexer MUX1 becomes " low " to enable the output enable stages of the English character generators CG5 and CG6.

Enable). At this time, select English characters to occur. When the output terminals Dl4 and Dl3 of the buffer BUF1 are all "low", the output of the NAND gate NA1 is "high", so the resistance of the NAND gate NA3 through the resistor Rl is "high". Since the type force terminal of the NAND gate NA3 through Rl is "high", the output of the NAND gate NA3 is "low" so that the output enable stage of the buffer line drivers BL1-BL2 (

) Is enabled, and Hangul generated from the Hangul alphabet / vowel character generator (CG1-CG4) is combined into the desired Hangul form through the ORA gate (OR2-OR17) and buffered through the buffer line driver (BL1-BL2). It is comprised so that it may be output to the shift register 8 of 1 degree | time.

4 is a flow chart according to the present invention, the first step of checking the specified Hangul, English mode and 40-character and 80-character mode of Hangul, and according to the embroidery (80/40 characters) mode of Hangul from the first step A second step of calculating the most significant bit of data to be displayed; a third step of determining a Korean character font according to the decision logic of the most significant bit calculated in the 40-character mode from the second stage; A fourth step of determining the Korean font at the current cursor position according to the decision logic of the most significant bit calculated in the 80 character mode from the second step, and a fifth step of outputting data of the Hangul characters determined in the third and fourth steps; have.

)으로 "로우"가 출력되어 영문캐릭터 제네레이터 (CG5,CG6)의 출력 인에이블단(OE)을 인에이볼 시킨다.Therefore, a specific embodiment of the present invention will be described in detail with reference to the configuration of FIGS. 1-3 and the flowchart of FIG. Designation command is inputted to the central processing unit (CPU), and information flags and character code data corresponding to English / Korean and 80/40 character modes are stored in the video RAM unit 10 through the multiplexer 3 together with the data. At the same time, the CPU controls the CRTC 70 to generate a synchronization signal suitable for the mode. That is, the CPU checks whether it is English or Korean in step (b) of FIG. 4 of the present invention, and checks whether it is in 40 or 80 character mode in step (d). In the case of (b), the central processing unit (CPU) stores the mode selection flag signal in the predetermined region of the video RAM (VRAM1) of FIG. 3 of the video RAM unit 10 through the multiplexer 3 for English processing. do. When stored in the video RAM VRAM1, the output terminals Dl3 and Dl4 of the buffer BUF1 become “high” so that the output of the NAND gate NA1 becomes “low” and the output terminal of the multiplexer MUX1 (

) Is outputted to enable the output enable stage OE of the English character generators CG5 and CG6.

The output of the NAND gate NA3 is " high " to disable the output enable end OE of the buffer line drivers BL1-BL2. Accordingly, even if the character data in the Hangul / vowel character generators CG1-CG4 is not outputted. Therefore, as described above, the output data of the video RAM VRAM2 processed and stored in the CPU is buffered in the buffer BUF2 and the address line of the English character generator CG5-CG6 through the output terminals D0-D7. A5-Al2), and when the low address signal RA0-RA3 generated by the CRTC 70 is input to the address line A0-A3 of the English character generator CG5-CG6, an English character character English characters are generated by specifying the addresses of generators CG5 and CG6.

The English characters generated at the output terminals DD0-DDl5 of the English character generators CG5 and CG6 are inputted to the shift register 8 of FIG. 1 and shifted according to the shift flocks provided by the CRTC 70. The shifted English letter signal is displayed on the CRT through the video output unit 9, and the English letter is displayed on the CRT according to the synchronization signal supplied from the CRTC 70. However, in the process of (b), the CPU is configured to set the designated flag according to the processing of the Hangul characters in the video RAM (VRAM1) of FIG. 3 of the video RAM unit 10 through the multiple (3). Check if the mode is 40 or 80 characters. In the 40 character mode in the step (d), the central processing unit (CPU) displays the position of the cursor in order to display the video RAM 10 through the multiplexer 3 in the form of the second (b) in the process (ㅁ). The specified data is calculated by the central processing unit (CPU) and output to the multiplexer 3 and the video RAMs VRAM1 and VRAM2. However, the actual action takes place almost simultaneously with the output of the data. This is because when the Korean character is operated in the 40-character mode, the first data (1 word) is the second (b) because the Hangul display data to be displayed on the screen is composed of two words (4 bytes) in order to display the Korean characters on the screen. The second data (two words) becomes the data on the right side of the second (b) diagram, and the left and right of the Hangul characters composed of two words in the 40-character mode as shown in the second (b) diagram. You will need to specify the UDATA.

When the first data is the display data 1 and the second data is the display data 2, the CPU multiplies the 2 byte data A of the display data 1 by 7FFFH in the step (). (A and 7FFF) The most significant bit MSB is set to " 0 " from the value multiplied by step (ㅁ), and then the display data 2 is calculated in step (iii).

In this example, 8000H is added to Hangul two-byte data (B) at the cursor position, and (B, OR, 8000H) is added. The most significant bit MSB is " 1 "

Therefore, the central processing unit (CPU) stores the values of the display data 1 and 2 calculated in the above (ㅁ, ㅂ) process through the multiplexer 3 in the video RAMs VRAM 1 and VRAM 2 of the video RAM unit 10. If the CPU recognizes the 80-character mode in the step (d), in order to display the character as shown in FIG. 2 (a), the Hangul 2 bytes ( Add 8000H to A). The most significant bit MSB is set to 1 from the value added in step (o) and stored in the video RAMs VRAM 1 and VRAM 2 of the video RAM unit 10 through the multiplexer 3. The video RAM VRAM1 of the video RAM 10 stores English / Korean designation and 80/40 mode setting flag information bits. The remaining data other than the VRAM1 and the VRAM2 are stored with code data for display in English / Korean.

)이 "하이"된다. 이때 영문 캐릭터 제네레이터(CG5,CG6)의 출력 인에이블단(

)이 디스에이블 상태로되어 영문문자 발생이 차단된다.Accordingly, the data stored in the video RAMs VRAM1 to VRAM2 and the data of the corresponding mode are output to the CRT. In the 40-character mode of the Hangul mode, the buffer BUF1 buffered the output of the video RAM VRMA1 is output to the output terminal D5. According to " 1 " or " 0 ", the left and right sides of the second (b) designate display data, and when the buffer BUF1 has the value of the output terminal Dl4 as "low", the output of the NAND gate NA1 is " High ", and the output of the NAND gate NA3 is" low ". In this case, the buffer line drivers BL1-BL2 are enabled to output an output. When the output of the NAND gate NA1 becomes “high” and is input to the multiplexer MUX1, the output terminal of the multiplexer MUX1 (

) Is "high". At this time, the output enable stage of the English character generator (CG5, CG6)

) Is disabled and English characters are blocked.

The outputs of the output terminals DO-D4 and D10-Dl4 of the buffers BUF1 and BUF2 are input to the multiplexer MUX2 and are selected. ORI) is input to the address signal (Al2, Al3) of the Hangul consonant character generator (CGI, CG3) to designate the initial consonant and the final consonant among Hangul consonants, and at the same time the address signal of the Hangul vowel character generator (CG2, CG4) It is inputted as (A10). In addition, the output signal of the OR gate OR1 is input to the AND gate AN1, and the buffers BUFI and BUF2 are supplied to the muldiplexer MUX2 according to the output of the row address signal RA3 generated by the CRTC 70. Select the output of the output terminals D0-D4 and D10-Dl4. Therefore, when the Hangul consonant character generators CG1 and CG3 are supplied as address signals, the first consonant and the final consonant may be generated differently with respect to the consonant among the Hangul consonants. When the outputs of the output terminals B5-D7 and D8-D9 of the buffers BUF1 and BUF2 are respectively input to the Hangul consonant / vowel character generation CG1-CG4, the multiplexer MUX2 and the ORA gate OR1 are respectively input. The Hangul characters are generated according to the signal specified by the address signal of the Hangul character generators CG1-CG4 as in the output received from the < RTI ID = 0.0 > The combined Hangul character data is driven in the buffer line drivers BL1 -BL2 and input to the shift register 8.

In the shift register 8, the shift register 8 is shifted for the shift clock generated by the CRTC 70 and displayed on the CRT through the video output unit 9. However, the CPU sets bits according to the data to be displayed according to the 80/40 character mode as described above, but sends a control signal to the CRTC 70 to match a predetermined register to a predetermined register inside the CRTC 70 according to the mode. Set the specified value so that the CRT generates vertical / horizontal sync frequency. The well-known fact that the vertical / horizontal synchronous frequency should be varied according to the size and mode of the above-described characters. Here, the CRTC 70 can be configured according to the 80- and 40-character modes specified by the CPU. A frequency with different horizontal synchronization is generated and supplied to the CRT.

On the other hand, in the 80-character mode as shown in FIG. 2 (a), since the pseudo-bit of the Hangul 2-byte mode is "1", the state of the output terminal Dl5 of the buffer BUF1 is continuously output with the state of "1". Under the control of the device CPU, the vertical / horizontal synchronization frequency generated in the CRTC 70 is supplied to the CRT differently. In the 80-character mode, the Hangul characters are generated in the same manner as the 40-character mode by enabling the buffer line driver BL1-BL2 by the output of the land gate NA3 and outputting the output terminal Q1 of the multiplexer MUX1. After disabling the English character generators CG5 and CG6 by using the multiplexer MUX2, the characters for the initial initial phonemes are selected by the Hangul character generators CG1 and CG3 and output from the buffers BUF1 and BUF2. Since the address of the Hangul character generators CG1-CG4 is designated according to data, the Hangul characters are generated and combined with the ORA gates OR2-OR17.

The Hangul character generation data combined in the OA gate (OR2-OR17) is driven by the shift clock generated by the CRTC 70 which is driven by the buffer line drivers BL1-BL2 and input to the shift register 8 to output the video. In accordance with the vertical / horizontal synchronization clock supplied to the CRT through the subpart 9, the 80-character Korean character is displayed at the current cursor position as shown in the second (a). There is an advantage that 40 characters of Korean characters and 80 characters of Korean characters can be selected and written using only the character generator without changing the reference hardware.

Claims (2)

Central processing unit (CPU), CRT, multiplexer (3), which receives commands according to the Korean / English and 80 / 40-character mode settings, and non-IRAM Lang (10) having random image data, The address signal is supplied to the English character generator 40 in which the character pattern is embedded in the fixed data, the Korean character generator 50 in which the Korean character pattern is embedded in the fixed data, and the video RAM 10 or the character generator. A character generation circuit having a CRT controller 70 for providing a synchronization signal to a CRT, comprising: buffering the output data of the video RAM 10, and outputting a flag signal of the most significant bit for setting the 80 or 40 character mode. A buffer unit 20 for outputting, a selector 30 for outputting a Hangul and English mode enable signal designated by the output of the buffer unit 20, a Korean initial and final phoneme selection signals, and the Hangul character generator ( On 50) Hangul characters for display, characterized in that configured to output data to the line buffer unit 66 to output to the shift register 8 to the driving line to be fully displayed on the CRT mode converter. A central processing unit (CPU), a video RAM 10 serving as an image data fixing device, a buffer unit 20 of an output buffer of the video RAM 10, and a selection unit 30 for selectively outputting an English / English enable signal. ), An English character generator 40 that is an English pattern character generator, a Korean character generator 50 that is a Korean pattern character generator, a line driver 60 that buffers the output data of the Korean character generator 50, and In the character generation method having a CRT controller 70 for controlling the display of the image, the Hangul / English mode and the Hangul 40 and 80-character mode specified according to the command input to the central processing unit (CPU) A first step of checking, a second step of calculating the most significant bit of the display data according to the embroidery mode (80/40) of the Hangul from the first step, and a 40-character mode is calculated from the second step Hangul characters according to the decision logic of the most significant bit The third step of determining the right font, the fourth step of determining the Hangul font at the current cursor position according to the decision logic of the most significant bit calculated in the 80 character mode from the second step, and the determination of the third and fourth steps. And a fifth step of outputting Korean character data.

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